Table 2.
Univariable and multivariable analysis of predictors of MTX non-response in all subjects and excluding those in remission at baseline
| Characteristic | All subjects | Excluding those in remission | ||||||
|---|---|---|---|---|---|---|---|---|
| Univariable | Stepwise multivariable n = 833, AUC = 0.77 (95% CI (0.73, 0.80)) |
Univariable | Stepwise multivariable n = 700, AUC = 0.72 (95% CI (0.68, 0.76)) |
|||||
| OR (95% CI) | p | OR (95% CI) | p | OR (95% CI) | p | OR (95% CI) | p | |
| Demographic and lifestyle factors | ||||||||
| Female sex | 1.13 (0.87, 1.46) | 0.37 | 1.20 (0.90, 1.59) | 0.22 | ||||
| Age (years) | 0.99 (0.98, 1.00) | 0.06 | 0.99 (0.98, 1.00) | 0.04 | ||||
| BMI (kg/m2) | 1.02 (1.00, 1.05) | 0.04 | 1.04 (1.02, 1.06) | < 0.01 | 1.05 (1.02, 1.08) | < 0.01 | ||
| Smoking: never | ref | ref | ref | ref | ||||
| Smoking: former | 1.20 (0.91, 1.59) | 0.19 | 1.23 (0.91, 1.65) | 0.18 | ||||
| Smoking: current | 1.78 (1.28, 2.48) | < 0.01 | 1.74 (1.22, 2.48) | < 0.01 | ||||
| Alcohol consumption: current | 1.14 (0.87, 1.49) | 0.34 | 1.13 (0.85, 1.51) | 0.40 | ||||
| Alcohol consumption: (units/fortnight) | 1.01 (1.00, 1.02) | 0.08 | 1.01 (1.00, 1.02) | 0.21 | ||||
| Coffee/tea consumption: (cups/day) | 1.03 (0.98, 1.09) | 0.20 | 1.04 (0.99, 1.10) | 0.12 | ||||
| IMD score (units) | 1.01 (1.00, 1.02) | 0.02 | 1.01 (1.00, 1.02) | 0.05 | ||||
| Disease-specific factors | ||||||||
| Symptom duration (months) | 1.00 (1.00, 1.00) | < 0.01 | 1.00 (1.00, 1.01) | < 0.01 | ||||
| RF positive | 0.66 (0.50, 0.88) | < 0.01 | 0.62 (0.45, 0.86) | < 0.01 | 0.57 (0.42, 0.76) | < 0.01 | 0.52 (0.37, 0.73) | < 0.01 |
| Satisfied the 1987 ACR criteria | 0.59 (0.43, 0.83) | < 0.01 | 0.66 (0.46, 0.94) | 0.02 | ||||
| HAQ score (units) | 0.76 (0.64, 0.90) | < 0.01 | 1.64 (1.25, 2.15) | < 0.01 | 0.92 (0.77, 1.11) | 0.39 | ||
| Co-morbidities: 0 | ref | ref | ref | ref | ||||
| Co-morbidities: 1 | 1.30 (0.97, 1.75) | 0.08 | 1.45 (1.06, 2.00) | 0.02 | ||||
| Co-morbidities: 2+ | 1.29 (0.96, 1.75) | 0.09 | 1.50 (1.08, 2.07) | 0.01 | ||||
| Creatinine (mg/dl) | 1.01 (1.00, 1.01) | 0.10 | 1.01 (1.00, 1.01) | 0.18 | ||||
| Disease activity | ||||||||
| Morning stiffness (minutes) | 1.00 (1.00, 1.00) | 0.01 | 1.00 (1.00, 1.00) | 0.18 | ||||
| TJC28 (joints) | 0.94 (0.92, 0.96) | < 0.01 | 1.06 (1.02, 1.10) | < 0.01 | 0.96 (0.95, 0.98) | < 0.01 | ||
| SJC28 (joints) | 0.92 (0.90, 0.94) | < 0.01 | 0.94 (0.92, 0.96) | < 0.01 | ||||
| CRP (mg/l) | 0.98 (0.97, 0.99) | < 0.01 | 0.99 (0.98, 0.99) | < 0.01 | ||||
| Patient VAS (mm) | 0.98 (0.97, 0.99) | < 0.01 | 0.99 (0.98, 0.99) | < 0.01 | ||||
| DAS28-CRP (units) | 0.54 (0.48, 0.60) | < 0.01 | 0.29 (0.23, 0.39) | < 0.01 | 0.63 (0.55, 0.71) | < 0.01 | 0.49 (0.41, 0.58) | < 0.01 |
| Pain VAS (mm) | 0.99 (0.99, 1.00) | < 0.01 | 1.00 (0.99, 1.00) | 0.26 | ||||
| Fatigue VAS (mm) | 1.00 (0.99, 1.00) | 0.29 | 1.00 (1.00, 1.01) | 0.21 | ||||
| Medication | ||||||||
| Oral or intramuscular steroids: current/recent | 0.96 (0.75, 1.24) | 0.76 | 0.97 (0.74, 1.27) | 0.82 | ||||
| NSAIDs: current | 1.02 (0.78, 1.32) | 0.90 | 1.08 (0.82, 1.43) | 0.58 | ||||
| csDMARDs: current | 1.31 (0.96, 1.79) | 0.09 | 1.37 (0.99, 1.91) | 0.06 | ||||
| csDMARDs: ever | 1.43 (1.07, 1.91) | 0.02 | 1.50 (1.11, 2.04) | 0.01 | ||||
| MTX starting dose (mg/week) | 0.97 (0.94, 1.02) | 0.22 | 0.98 (0.94, 1.02) | 0.30 | ||||
| Psychosocial factors | ||||||||
| HADS Anxiety (units) | 1.02 (0.99, 1.05) | 0.21 | 1.07 (1.03, 1.12) | < 0.01 | 1.04 (1.01, 1.07) | 0.01 | 1.11 (1.07, 1.15) | < 0.01 |
| HADS Depression (units) | 0.98 (0.95, 1.01) | 0.19 | 1.01 (0.98, 1.05) | 0.57 | ||||
| BMQ medication necessity (units) | 0.98 (0.94, 1.01) | 0.23 | 0.99 (0.95, 1.03) | 0.50 | ||||
| BMQ medication concerns (units) | 1.03 (0.99, 1.06) | 0.14 | 1.03 (0.99, 1.07) | 0.14 | ||||
| BMQ necessity-concerns (units) | 0.98 (0.95, 1.00) | 0.08 | 0.98 (0.95, 1.01) | 0.16 | ||||
| IPQ negative illness representation | 0.88 (0.68, 1.14) | 0.33 | 1.14 (0.86, 1.51) | 0.37 | ||||
Abbreviations: BMI body mass index, IMD Index of Multiple Deprivation, RF rheumatoid factor, HAQ Health Assessment Questionnaire, TJC28 tender 28-joint count, SJC28 swollen 28-joint count, CRP C-reactive protein, VAS visual analogue scale, DAS28 Disease Activity Score based on the 28-joint count, NSAIDs non-steroidal anti-inflammatory drugs, csDMARDS conventional synthetic disease-modifying anti-rheumatic drugs, HADS Hospital Anxiety and Depression Scale, BMQ Beliefs about Medicines Questionnaire, IPQ Illness Perception Questionnaire